Heat exchanger



March 28, 1967 OWEN 3,311,163

HEAT EXCHANGER Filed June 25, 1965 INVENTOR. n 5. Owen I ATTORNEYS United States Patent 3,311,163 HEAT EXCHANGER Nathan B. Owen, Minneapolis, Minn, assignor to TWll'l Temp Inc., Minneapolis, Minn., a corporation of Minnesota Filed June 25, 1965, Ser. No. 467,051 1 Claim. (Cl. 165-55) exchange member in the convector assembly. The finned tube is commonly positioned upon a plurality of supporting members which extend from a wall mounting plate. As the tube expands and contracts with changes in temperature, the fins move slightly in a linear relation to the supporting means upon which they are placed, and. there is suflicient movement of the fins against the supports over a length of such tube to cause unfavorable noise and possibly damage to the edges of the fins.

Such problems are avoided in the present invention by providing a unitary structure which includes partial covering on the lateral edges of the fins which is adhered thereto. Such a cover prevents contact with the sharp edges and corners of the fins and provides a relatively frictionless surface which may rest upon a plurality of supporting members to allow free movement of the heating core as it expands and contracts with changes in temperature. More particularly, the present invention provides a means of rigidly securing each fin in a fixed position to prevent bending of the fins. Where the edges of each fin are free to move, any bending of the fins re-v sults in partially or completely closing the channels between the fins and thereby restricting the flow of air through the core. The partial covers on the lateral edges of the fins further provides a partial enclosure which channels the flow of air over the fins and directs its even flow through the convertor assembly.

The present invention more particularly provides partial covers adhered to the lateral edges of the fins which are of a material that will expand and contract at the same rate as the tube upon which the fins are aflixed, given a normal difference in temperature between the tube and the edges of the fins, so that the whole heating core expands and contracts as a single unit with no relative movement between parts.

The tube of the heat exchange member is preferably composed of copper, while the fins are composed of aluminum, and the partial covers are also preferably composed of aluminum and are firmly adhered to the edges of the fins, preferably by an adhesive material. The temperature at the edge of the fins is normally about three-fourths the temperature of the tube carrying the heated fluid. The coeflicient of expansion of copper is approximately three-fourths as large as the coefiicient of expansion of aluminum, and thus as linear expansion of the copper tube occurs, there is almost equal expansion and contraction of the aluminum covers to allow expansion and contraction as a one-piece unit.

An object of this invention is to provide a heat exchange member for use in a baseboard convector assembly which is composed of a finned tube bonded at its lateral extremities to partial coverings to form a unitary member that will silently move with respect to supporting portions of the convector assembly during expansion and contraction of the parts caused by temperature changes.

Another object is to provide a heat exchange member which is constructed to give a maximum of heat exchange between the fluid passing through said member and the air that is channeled through the convector.

FIG. 1 is a fragmentary perspective View of a baseboard convector assembly with parts cut away to show the interior of the assembly; and

FIG. 2 is a partially separated vertical section of a heat exchange member forming the present invention.

Referring to the drawing, the convector assembly embodying the present invention is designated by general reference numeral 4. A wall mounting plate 6 is adapted to be secured by means, not shown, to a wall of an enclosure. A front cover plate 8 is disposed forwardly from the wall mounting plate 6 to form a convection channel between these plates, designated by reference numeral 10. A multiplicity of supporting brackets are aflixed at spaced intervals to the wall mounting plate 6, and one of such brackets is illustrated in FIG. 1 and designated by reference character 12. The bracket 12 is formed with an upper arm 14 which engages an upper edge 16 of the front cover plate 8, and a second arm 18 extends from bracket 12 to engage a lower portion 20 of the front cover plate 8, as well as a heat exchange member designated by general reference numeral 22, that forms the present invention and is shown in enlarged scale in FIG. 2.

The heat exchange member 22 is composed Of a central tube 24 that is adapted to convey a heat exchange fluid, such as hot water. The tube 24 is preferably composed of copper. Spacially aflixed to the outer surface of tube 24 and extending transversely therefrom are .a multiplicity of rectangular fins '26 composed of a heat conducting metal, preferably aluminum. Each of the fins 26 is embossed or otherwise creased, as indicated at 27, to provide parallel vertical lines of fiexture for reasons to be discussed hereinafter.

Surrounding the lateral extremities of fins 26 are a pair of partial covers which are of U-shaped configuration, and designated by reference characters 28 and 30. These partial covers 28 and 30 are also composed of heat conducting material, and preferably aluminum. The partial cover 28 has angular corner portions 32, '34, which envelop the corners of one side of the several fins 26, and terminate in rolled portions 36, 38. The partial cover 30 has angular corner portions 40, 42, which envelop the corners of the other side of the several fins 26 and terminate in rolled portions 44, 46. Each of the partial covers 28, 30, are bonded to the lateral edges of the several fins 26 by one or more layers of an organic adhesive material indicated by reference character 48. The partial cover 30 is shown separated from the left hand edges of the fins 26 to illustrate one manner in which the adhesive bonding material is applied to the partial covers prior to assembly. When the heat exchange member 22 is fully assembled, the rolled portions 38, 46, on the lower surface thereof form tracks for supporting the assembly 22 on the arms 18 of the several brackets 12, and the rolled portions 36, 44, form alternative tracks in the event that the structure is reversed in position.

In practice, a heat exchange fluid, such as heated water is circulated through the center metallic tube 24, and since copper is a good conductor of heat, the temperature of the fluid will be transferred to the fins 26 and also to the partial covers 28 and 30. The heat thus imparted from the fluid to the tube, fins and partial covers, is dissipated to the air flowing upwardly through the convection channel 10. It will be recognized that although the metal has good heat conducting qualities, the various members will not all be of uniform temperature. Assuming that the temperature of the fluid passing through the conduit 24 is substantially 200 F., the temperature of the fins 26 will be at a somewhat lower temperature, while the temperature of the partial covers will be approximately 150 F. The coeflicient of expansion of copper is .000009 inch per degree change in temperature, While the coeflicient of expansion of aluminum is .00001234 inch per degree of change in temperature, so that aluminum expands at a rate approximately 25% faster than copper. However, since a temperature loss occurs between the center tube 24 and the partial covers 28 and 30, the linear expansion of the partial covers will be substantially equal to the linear expansion of tube 24. The fins 26 being located between tube 24 and the partial covers 28 and 3t), and being bonded on their outer edges to the partial covers 23 and 30 may expand at a rate greater than the partial covers, and for that reason the embossing or creases 27 in the fins 26' provide areas for flexture to compensate for differences in the rate of expansion. Such flexure dill, however, be silent and the metal at the opposite ends of the embossing 27 will tend to return the fins to their normal straight line position when the temperature of the fins is reduced.

The total effect of the construction of the heat exchanger 22 is to provide a maximum of heat exchange between the fluid passing through tube 24 and the air surrounding and flowing through member 22. Lateral expansion of the fins is accommodated by the embossing 27 while linear expansion of the entire assembly is accommodated by the variable expansion of the partial covers with respect to the tube 24. This arrangement provides for a silent movement of the assembly on the tracks or rolled portions of the partial covers relative to the arms 13 of the brackets 12.

The principal advantage of this invention is in the provision of a heat exchange assembly, which through its integrated construction expands and contracts as a unit and is, therefore, capable of silent movement on the supporting structure. A

My invention is defined in the terms of the appended claim.

I claim:

A baseboard convector heat exchange member, comprising a metallic tube adapted to convey a heat exchange fluid, a multiplicity of rectangular metallic fins spacially aflixed to the outer surface of said tube and extending transversely to said tube, each of said fins formed with parallel vertically extending embossing therein, a pair of partial covers formed of a metal having a greater coefficient of expansion than said metallic tube, and an adhesive material flexibly bonding said partial covers on the opposite lateral sides of all of said. fins and integrating the assembly into a unified structure in which there is no independent movement of parts during a substantial temperature change of the fluid conveyed within said tube.

References Cited by the Examiner UNITED STATES PATENTS 2,189,652 2/1940 Lehman 1s1 2,625,378 1/1953 Nason 165171 3,263,746 8/1966 Becker et a1. 165-55 ROBERT A. OLEARY, Primary Examiner.

CHARLES SUKALO, Examiner. 

